Gholam Saleh, Hadermann Joke
EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
EMAT, University of Antwerp, Groenenborgerlaan 171, Antwerp 2020, Belgium.
Ultramicroscopy. 2024 Dec;266:114022. doi: 10.1016/j.ultramic.2024.114022. Epub 2024 Aug 5.
Nowadays, 3D Electron Diffraction (3DED) is widely used for the structure determination of sub-micron-sized particles. In this work, we investigate the influence of the acceleration voltage on the quality of 3DED datasets acquired on BaTiO nanoparticles. Datasets were acquired using a wide range of beam energies, from common, high acceleration voltages (300 kV and 200 kV) to medium (120 kV and 80 kV) and low acceleration voltages (60 kV and 30 kV). It was observed that, in the integration process, R increases as the beam energy is reduced, which is mainly due to the increased dynamical scattering. Nevertheless, the structure was solved successfully in all cases. The structure refinement was comparable for all beam energies with small deficiencies such as negative atomic displacements for the heaviest atom in the structure, barium. Including extinction correction in the refinement noticeably improved the model for low acceleration voltages, probably due to higher beam absorption in these cases. Dynamical refinement, however, shows superior results for higher acceleration voltages, since the dynamical refinement calculations currently ignore inelastic scattering effects.
如今，三维电子衍射（3DED）被广泛用于亚微米级颗粒的结构测定。在这项工作中，我们研究了加速电压对在钛酸钡纳米颗粒上获取的3DED数据集质量的影响。使用了从常见的高加速电压（300 kV和200 kV）到中等（120 kV和80 kV）以及低加速电压（60 kV和30 kV）的广泛束流能量来获取数据集。观察到，在积分过程中，随着束流能量降低，R值增加，这主要是由于动态散射增加所致。然而，在所有情况下都成功解析了结构。对于所有束流能量，结构精修情况相当，但存在一些小缺陷，例如结构中最重的原子钡的负原子位移。在精修中纳入消光校正显著改善了低加速电压下的模型，这可能是因为在这些情况下束流吸收更高。然而，动态精修在较高加速电压下显示出更好的结果，因为目前的动态精修计算忽略了非弹性散射效应。
